As the light-emitting material having phosphorescence in visible region used for a light emitting layer of light-emitting device, devices using a metal complex (hereafter may be referred to as triplet light-emitting complex) showing light emission from triplet excited state have been known.
As the triplet light-emitting complex, for example, Ir(ppy)3 which includes iridium as the central metal, (Appl. Phys. Lett., 75, 4(1999)), PtOEP which includes platinum as the central metal (Nature, 395, 151(1998)), Eu(TTA)3phen which includes europium as the central metal (Jpn. J. Appl. Phys., 34, 1883(1995)) are known.

However, for forming a light emitting layer using the above well-known triplet light-emitting complexes, only the methods, such as vacuum-depositing method, are applicable, and it has been difficult to form a light emitting layer by coating method.